Vulnerability-Lookup

RHSA-2026:70754

Vulnerability from csaf_redhat - Published: 2026-09-23 00:00 - Updated: 2026-09-24 10:25

Summary

security update for unbound

Severity

Critical

Notes

Title of the patch: security update for unbound

Description of the patch: This security update provides a functional equivalent of RHSA-2026:70754. The original Red Hat(R) advisory is available from the Red Hat web site at https://access.redhat.com/errata/RHSA-2026:70754.

Patchnames: RHSA-2026:70754

CVE-2026-81634

8.1 (High)


                
                  CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Recommended 6 products

Product	Version	Remediation
Unresolved product id: SUSE Liberty Linux 8:python3-unbound-0:1.16.2-5.14.el8_10.4.x86_64	—	Vendor Fix
Unresolved product id: SUSE Liberty Linux 8:unbound-0:1.16.2-5.14.el8_10.4.x86_64	—	Vendor Fix
Unresolved product id: SUSE Liberty Linux 8:unbound-devel-0:1.16.2-5.14.el8_10.4.i686	—	Vendor Fix
Unresolved product id: SUSE Liberty Linux 8:unbound-devel-0:1.16.2-5.14.el8_10.4.x86_64	—	Vendor Fix
Unresolved product id: SUSE Liberty Linux 8:unbound-libs-0:1.16.2-5.14.el8_10.4.i686	—	Vendor Fix
Unresolved product id: SUSE Liberty Linux 8:unbound-libs-0:1.16.2-5.14.el8_10.4.x86_64	—	Vendor Fix

Threats

Impact important

CVE-2026-81642

8.1 (High)


                
                  CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Recommended 6 products, the same list as for CVE-2026-81634

Threats

Impact important

CVE-2026-82717

8.1 (High)


                
                  CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Recommended 6 products, the same list as for CVE-2026-81634

Threats

Impact important

References

11 references

URL	Category
https://www.suse.com/support/security/rating/	external
https://ftp.suse.com/pub/projects/security/csaf/r…	self
https://www.suse.com/security/cve/CVE-2026-81634/	self
https://www.suse.com/security/cve/CVE-2026-81642/	self
https://www.suse.com/security/cve/CVE-2026-82717/	self
https://www.suse.com/security/cve/CVE-2026-81634	external
https://bugzilla.suse.com/1280409	external
https://www.suse.com/security/cve/CVE-2026-81642	external
https://bugzilla.suse.com/1280411	external
https://www.suse.com/security/cve/CVE-2026-82717	external
https://bugzilla.suse.com/1280412	external

JSON

To clipboard

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          "text": "In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in that can progressively corrupt heap memory and under certain systems and compilation options could lead to remote code execution. The vulnerability starts when CNAME synthesis during an upstream response needs to enforce(rewrite) a max TTL value in the packet buffer. Coupled with a compression pointer that points to the overwritten value and invalidates the domain name, it leads to an error path that does not properly move the buffer position and allows for the heap buffer overflow. Since this is heavily reliant on heap memory layout, results are memory corruption that eventually leads to a crash and under specific systems and compilation options remote code execution.",
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CVE-2026-81634 (GCVE-0-2026-81634)

Vulnerability from cvelistv5 – Published: 2026-09-16 08:30 – Updated: 2026-09-16 14:32

Title

Possible heap buffer overflow during DNSSEC canonicalization

Summary

In NLnet Labs Unbound up to and including 1.26.0, a 255 length query name with a large TCP response can lead to a heap buffer overflow during the RRSet canonicalisation routine. This is caused by missing to add the first owner name into the buffer length check. A malicious actor operating a malicious name server or tampering with an incoming response to Unbound (canonicalisation happens before DNSSEC validation), can trigger the vulnerability.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-16 14:32 UTC

CWE

CWE-122 - Heap-based Buffer Overflow

Assigner

NLnet Labs

References

1 reference

URL	Tags
https://www.nlnetlabs.nl/downloads/unbound/CVE-20…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
NLnet Labs	Unbound	Affected: 0 , < 1.26.1 (semver)

Date Public

2026-09-16 00:00

Credits

Vlatko Kosturjak (Marlink Cyber)

Show details on NVD website

JSON

To clipboard

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CVE-2026-81642 (GCVE-0-2026-81642)

Vulnerability from cvelistv5 – Published: 2026-09-16 08:30 – Updated: 2026-09-16 14:32

Title

Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY

Summary

In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in the DNSSEC validator that enables denial of service and possible remote code execution as a result of digesting DNSKEYs. A DNSKEY with an owner compression pointer to its own RDATA can overflow the digest buffer. Remote code execution is possible through attacker controlled data. An adversary can exploit the vulnerability by controlling a malicious zone and querying a vulnerable Unbound.

Severity

9.1 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:U/U:Red

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-16 14:30 UTC

CWE

CWE-122 - Heap-based Buffer Overflow

Assigner

NLnet Labs

References

1 reference

URL	Tags
https://www.nlnetlabs.nl/downloads/unbound/CVE-20…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
NLnet Labs	Unbound	Affected: 0 , < 1.26.1 (semver)

Date Public

2026-09-16 00:00

Credits

Yuqi Qiu (Nankai University, AOSP Lab) Xiang Li (Nankai University, AOSP Lab)

Show details on NVD website

JSON

To clipboard

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CVE-2026-82717 (GCVE-0-2026-82717)

Vulnerability from cvelistv5 – Published: 2026-09-16 08:31 – Updated: 2026-09-16 14:15

Title

CNAME synthesis could lead to heap corruption

Summary

In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in that can progressively corrupt heap memory and under certain systems and compilation options could lead to remote code execution. The vulnerability starts when CNAME synthesis during an upstream response needs to enforce(rewrite) a max TTL value in the packet buffer. Coupled with a compression pointer that points to the overwritten value and invalidates the domain name, it leads to an error path that does not properly move the buffer position and allows for the heap buffer overflow. Since this is heavily reliant on heap memory layout, results are memory corruption that eventually leads to a crash and under specific systems and compilation options remote code execution.

Severity

8.4 (High)


                        
                          CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:U

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-16 14:15 UTC

CWE

CWE-122 - Heap-based Buffer Overflow

Assigner

NLnet Labs

References

1 reference

URL	Tags
https://www.nlnetlabs.nl/downloads/unbound/CVE-20…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
NLnet Labs	Unbound	Affected: 0 , < 1.26.1 (semver)

Date Public

2026-09-16 00:00

Credits

Ben Morris (Anthropic)

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

RHSA-2026:70754

CVE-2026-81634 (GCVE-0-2026-81634)

CVE-2026-81642 (GCVE-0-2026-81642)

CVE-2026-82717 (GCVE-0-2026-82717)

Tags

Sightings

Nomenclature

Related by attack behaviour